Merge tag 'v4.18.14' into kernel-4.18

[android-x86/kernel.git] / fs / proc / base.c

diff --git a/fs/proc/base.c b/fs/proc/base.c
index aaffc0c..988c66e 100644 (file)
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -94,6 +94,7 @@
 #include <linux/sched/stat.h>
 #include <linux/flex_array.h>
 #include <linux/posix-timers.h>
+#include <linux/cpufreq_times.h>
 #include <trace/events/oom.h>
 #include "internal.h"
 #include "fd.h"
@@ -407,6 +408,20 @@ static int proc_pid_stack(struct seq_file *m, struct pid_namespace *ns,
        unsigned long *entries;
        int err;
 
+       /*
+        * The ability to racily run the kernel stack unwinder on a running task
+        * and then observe the unwinder output is scary; while it is useful for
+        * debugging kernel issues, it can also allow an attacker to leak kernel
+        * stack contents.
+        * Doing this in a manner that is at least safe from races would require
+        * some work to ensure that the remote task can not be scheduled; and
+        * even then, this would still expose the unwinder as local attack
+        * surface.
+        * Therefore, this interface is restricted to root.
+        */
+       if (!file_ns_capable(m->file, &init_user_ns, CAP_SYS_ADMIN))
+               return -EACCES;
+
        entries = kmalloc_array(MAX_STACK_TRACE_DEPTH, sizeof(*entries),
                                GFP_KERNEL);
        if (!entries)
@@ -2994,6 +3009,9 @@ static const struct pid_entry tgid_base_stuff[] = {
 #ifdef CONFIG_LIVEPATCH
        ONE("patch_state",  S_IRUSR, proc_pid_patch_state),
 #endif
+#ifdef CONFIG_CPU_FREQ_TIMES
+       ONE("time_in_state", 0444, proc_time_in_state_show),
+#endif
 };
 
 static int proc_tgid_base_readdir(struct file *file, struct dir_context *ctx)
@@ -3372,6 +3390,9 @@ static const struct pid_entry tid_base_stuff[] = {
 #ifdef CONFIG_LIVEPATCH
        ONE("patch_state",  S_IRUSR, proc_pid_patch_state),
 #endif
+#ifdef CONFIG_CPU_FREQ_TIMES
+       ONE("time_in_state", 0444, proc_time_in_state_show),
+#endif
 };
 
 static int proc_tid_base_readdir(struct file *file, struct dir_context *ctx)